Pliz same body help me

You've already seen the value of 9.8 in this lesson. what's this value called? what quantity does it represent?

The gun from the crime scene shows tool marks where the serial numbers are ground off. there are also tool marks on the bullets left behind. what information can the tool marks on the bullets and gun provide about the crime? what type of evidence does this information provide, individual or class?

A200 g lead frying pan gains 2000 joules of heat. what is the change in temperature